Changes in soil organic carbon concentration, chemical composition and aggregate stability as influenced by tillage systems in the semi-arid and semi-humid area of North China

Abstract

Transition from conventional tillage to no-tillage may alter the depth distribution of soil organic carbon (SOC) and its chemical composition. The effects of 15 yr contrasting tillage systems on soil aggregation and the concentration and chemical composition of SOC were investigated in a semi-arid and semi-humid area of North China. Three treatments were established in 1996, including conventional tillage with (CTS) and without (CT) straw incorporation, and no-tillage with straw mulching (NTS). 13 C nuclear magnetic resonance (NMR) spectroscopy was used to quantify the chemical characteristics of SOC in the 0-10 and 10-20 cm layers. NTS had a higher SOC stratification ratio than the CTS and CT. Aggregate stability, as indicated with the mean weight diameter, was higher for NTS and CTS than that for CT. SOC occluded in the >1 mm fraction was higher under NTS and CTS than under CT. Both NTS and CTS had more aliphatic carbon than CT did, and CT contained more aromatic carbon in the 0-20 cm layer. We concluded that NTS increased aggregate stability, enhanced SOC stratification, and altered the chemical composition of SOC in the plow layer, and could be a viable option for improving soil quality in the study area.

Effect of Tillage Treatment on the Diversity of Soil Arbuscular Mycorrhizal Fungal and Soil Aggregate-Associated Carbon Content

“…The mean aggregates size is known to decrease as tillage is intensified (Sheehy et al, 2015). When compared to conventionally tillage treatment, no tillage with crop straw return could enhance soil structural stability, this might be due to the increased bulk SOC concentration in the semi-arid and semi-humid area of North China (Du et al, 2017).…”

Long‐term effects of nitrogen and phosphorus fertilization on soil aggregate stability and aggregate‐associated carbon and nitrogen in the North China Plain

“…The OC concentration decreased in the 0.053‐ to 0.25‐mmaggregates in soil, probably through the fast decay rates of old C in these fractions, compared with large macroaggregates (>2 mm) (Fröberg et al., 2013). In addition, changes in aggregate size and stability can indicate changes in soil structure and quality (Du et al., 2017b). The effects of different sized aggregates on nutrient retention and supply in soil vary (Lipiec, Walczak, & Witkowska‐Walczak, 2007), possibly due to different microbial decomposition rates in each size of aggregate.…”

The effect of agroecosystem management on the distribution of C functional groups in soil organic matter: A review

“…2 ). Tillage facilitates the degradation of lipids, fatty acids, alkanes, and alkenes (Du et al 2017 ; Laudicina et al 2014 ; Shrestha et al 2015 ), thereby providing more decomposed SOC structures consisting of aromatic groups including phenols, lignin monomers, and alkyl-aromatics structures (Assunção et al 2019 ; Du et al 2017 ; Gao et al 2021 ; Laudicina et al 2014 ; Shrestha et al 2015 ). On the other hand, relative to tillage, the rate of decomposition may or has been shown to be lower under NT (Martins et al 2011 ) resulting in the accumulation of more labile SOC (e.g., carbohydrates and O-alkyl C) (Gao et al 2021 ).…”